leland



2 Sheets-Sheet 1.

(No Model.)

S. D. LELAND.

TAP DRIVING HEAD.

No. 393,511. Patented Nov. 27, 1888.

111mm 1'; 5m W.

2 Sheets-Sheet 2.

(No Model.)

S. D. LELAND.

. TA]? DRIVING HEAD. M2393 Patented Nov. 2'7, 1888.

1'5. l 1,13 i O r' w o O '1 I O O I? I I 1 H I I O I I I I IDTUIE s g ES Q I IUVEIIIUL 6 071W, MQGWW.

I I a UNTTED STATES PATENT OFFICE.

SANFORD D. LELAND, OF HOLYOKE, MASSACHUSETTS, ASSIGNOE OF TWOTHIRDS- TOGEORGE S. LEWIS AND FRANK E. FAY, BOTH OF SAME PLACE.

TAP-DRIVING HEAD.

SPECIFICATION forming part of Letters Patent No. 393,511, dated November27, 1888.

Application filed March 19, 1888.

, tion, reference being had to the accompanying drawings, forming partthereof.

The object of my invention is to provide a tap-head which will comprisewithin itself means for holding and revolving a screwtap, and also forautomatically stopping the revolution of the tap as the end of thelatter ap' proaches the bottom of the hole or orifice being tapped.

To this end my invention consists in a taphead comprising within itselfafriction-clutch, by means of which a revolving movement is transmittedfrom a revolving spindle to the tap, and automatic releasing devices forrendering said clutch inoperative to turn the tap as the end of thelatter approaches the bottom of the hole within which it is operating.

My invention also comprises certain details of construction hereinafterfully described, and particularly pointed out in the-claims.

Referring to the drawings, in which like letters designate like parts inthe several figures, Figure l is a side elevation of the parts composingthe tap-head as they appear previous to being assembled. Fig. 2 is asimilar view of the same parts after being assembled. Fig. 3 is avertical section of the parts as shown in Fig. 1. Fig. 4. shows theposition of the releasing devices during the operation of the tap. Fig.5 shows the position of the same parts after being tripped. Fig. 6 is aplan view of the tap-receiving hub. Fig. 7 is a similar view of theclutch holding and releasing wedges and their toggle-joint connection.Fig. 8 is a plan view of the upper end of the tap and an inverted planof the bushing by which it is held in its hub.

The letter A designates the spindle having the stem or, by means ofwhich the tap-head is adapted to be secured to the spindle of thedrill-press by which it is operated. I have deemed it to be unnecessaryto show the press,

as my invention relates wholly to the tap- Serial No. 267.618. (Nomodel.)

head, and because it will be understood by persons skilled in the art towhich the invention relates that byinserting the stem of spindle Awithin the socket in the spindle of the ordinary drill-press the formercan be revolved and also caused to advance and reeede at will. At theend opposite to said stem a the spindleAterminates in the annular flangea, from the face of which project two lugs, a, preferably located atdiametrically-opposite points on said flange, as shown. At its lower endspindle A is provided with a central bore to receive the stem 1) of hubB and at the inner end of said bore with an interior chamber,a Anorifice,a*, extends laterally through the shell of the spindle into saidchamber, and an interior lug, a extends upwardly from the bottom of saidchamber, both for a purpose presently to be described.

The letter B designates the hub, having at its upper end stem b, adaptedto fit loosely within the bore of spindle A and to project withinchamber a said stem at its upper end being provided with a transverseorifice to receive a pin, 1), which pin, being of greater length thanthe diameter of the bore in the spindle, serves to retain the hub andspindle in operative engagement with each other, while permitting alimited movement longitudinally and a free rotary movement of the stem bwithin the spindle. At its lower end hub B is bored centrally to receivethe tap, and at the inner end of the socket thus formed it is providedwith an interior chamber, If, of less diameter. In order to adapt thehub to receive and hold taps of different sizes, I prefer to provide thetaps G with a bushing, c, the outer diameter of which is substantiallythat of the bore of the hub,s0 as to fit closely therein, while theinner diameter of each bushing will correspond with that of theparticular tap with which it is designed to be used. Ialso prefer tomake the upper end of the tap and an orifice in the head of the bushingof corresponding angular conformation, as shown in Fig. 8, whereby theformer is prevented from revolving within the latter. To secure thebushings 0 within the hub, I provide the latter with an interior gib, band with an adjustingscrew,

outer diameter ofwhich correspondste'that' I), hearing at its inner endagainst said gib, whereby the latter can be tightened against thebushing. A screw, 12'', having its head located in a countersunkdepression in the hub, is inserted at its inner end into said gib nearthe upper end of the latter, and a coil-spring hearing at one endagainst the bottom of the depression in the hub and at the other endagainst the head of said screw flexibly retains the gib in its position.In the plane of the lower end of the chamber I) the hub B is pro videdwith an opening, I), extending transversely through it, and immediatelyin front ofor below said opening with an annular flange, 1/, having thesame outer diameter as flange a of the spindle. Seated within radialgrooves in the upper or rear face of said flange I) are two blocks, badapted to have a limited movement toward and away from each other. Tothe inner end of each of said blocks is pivoted a link, I)", the freeends olwhich links project within a transversely-slotted plug, 1), wherethey are secured by a pivot, b, passing through said plug across theslot therein. Said links and plug thus form a togglejoint, and said plugbeing fitted loosely within chamber b, it follows that by moving theplug upwardly within said chamber the blocks b will be drawn inwardly ortoward each other, and by moving the plug downwardly said blocks will bemoved outwardly or away from each other. Upon their upper surface theblocks Z) arcinclined downwardly toward their outer ends at aslightangleto their bottom surface, as sh own.

The letter D designates a bearingring, the

of flanges a and b the inner surface of which is beveled, as shown, andwhich is provided with recesses (Z in its lower surface to receiveloosely the ends of the blocks b The letter E designates a secondbearingring whose outer diameter is slightly less than the innerdiameter of ring D, and the outer surface of which is beveled tocorrespond with the inner surface of said ring D, whereby it is adaptedto closely fit within the latter ring, as shown in Figs. 2, L, and 5.The lower sur: face of said ringE is also preferably beveled tocorrespond with the inclined upper surfaces of blocks b, as shown, andupon its upper surface said ring is provided with two lugs, e, locatedat diametrically-opposite points thereon. The bearing-ring D is securedto flange b of the hub by screws or bolts passed therethrough andentering holes I) in the flange. (See Fig. 6.) The rings D E thus form afriction-clutch by which, when the latter is closely held within theformer, motion imparted to ring E will be transmitted to ring D and hubB. Said ring E, however, is capable of a slight vertical movement withinring D, and its position therein is governed by the position of blocks1)", which act as wedges against its lower surface. It will be obvious,therefore, that when said blocks occupy their outermost positions ring'Dand hub B will move in unison with ring E, and when said blocks occupytheir innermost positions said ring E can revolve freely without turningring D or hub 13.

When the parts are assembled, byinserting the stem of hub 13 withinspindle A and inserting pin b through orifice a in the spindle andthrough the orifice in the upper end of stem I), and the spindle islowered upon the hub, the lugs a" on the former are brought withinthcplane of revolution of lugs e on ring E, and by their contacttherewith transmit the revolving movement of the spindle to said ring.When the lugs a and c are in engage mentwith each other, pin Z) liesabove the plane of lug a in chamber a of the spindle and is free torevolve within said chamber,

when, by releasing the friction-clutch D E,hub

B becomes stationary, while the spindle and ring E continue theirrevolving movement. By raising the spindle, however, until the pin 1) isbrought into contact with-the bottom of chamber a" and lugs c areelevated above the plane of lugs e the lug c is brought within the planeof said pin, and by its cont-act therewith causes hub B to revolve withthe spindle in withdrawing the tap from its orifice after the completionof its work. The devices which govern the position of plug 1) and blocksb are a coil-spring, Z), located in chamber If above the plug andnormally retaining it in its lowest position, and a rod, 0, extendingcentrally through the tap and projecting be yond the ends thereof, aflange at the upper end of said rod retaining it within the tap. Saidrod is free to move lengthwise within the tap, and, until the latterapproaches the bottoms! the orifice within which 'it'is' open" ating,occupies the position shown in Fig. 4. By the continued movement of thetap the lower end of said rod is brought into contact with the bottom ofthe orifice and it is gradually elevated within the tap until its upperend abuts against the bottom of plug b, and by elevating the latteragainst the stress of spring I) and moving blocks 1) inwardly itreleases the clutch D E, and thereby stops the movement of the tap.

I have shownthe hub as being. provided.

with a shoulder, I), immediately above flange b, said shoulder havingits upper surface beveled to correspond with the bevel of thelowersurface of ring E, whereby said shoulder is adapted to support said ringwhen the blocks b are drawn inwardly; but it is obvious that other meansfor supporting said ring can be employed, and I do not wish to limitmyself to the use of such shoulder.

The operation of the tap-head thus constructed will be obvious from theabove description. The stem a of spindle A being secured within thespindle of a drill-press or within the head-stock of a lathe, and thetap O,corresponding in size to the particular orilice to be tapped,being inserted in hub B by lugs a e and rings D E to hnb B and the tap,the blocks 1) and rod 0 being in the position shown in Figs. 2and 4.When the tap reaches the bottom of the orifice,the red 0 moves theblocks b" to the position shown in Fig. 5, as previously described, andthe tap ceases to revolve. The movement of the drill-press spindle orlathe head-stock is then reversed in the usual manner, and, the reversemovement of spindle A being transmitted to hub B through pin 1) and luga, the tap is drawn from the orifice and the operation is completed.

It will be observed that the tap-head herein described is whollyautomatic,so far as stopping the movement of the tap isconcerned,thereby avoiding all possibility of injury to the tap throughthe carelessness of the operator. It will be observed, furthermore, thatby varying the length of red O the movement of the tap can be stopped atany desired distance above the bottom of the orifice in which itopcrates when it is not desired to tap said orifice entirely to thebottom thereof. The tap-head herein described is also adapted to tapholes which extend entirely through the material in which they arelocated in the usual manner, and its automatic feature can be utilizedin such case by arranging a suitable stop upon the rear side of thestock and opposite the orifice extending thcrethrouglnwith which the endof rod 0 can contact as the tap approaches the rear end of said orifice.

I do not wish to limit myself to the construction herein described inall of its various details, as modifications therein can be made withoutdeparting from the spirit of my invention.

Having thus fully described my invention, what I claim, and desire tosecure by Letters Patent, is

1. The self acting taplieadherein described, consisting of a hub havingasocket to receive the tap, a spindle opcratively connected with saidhub by means of a clutch, a tap seatcdin the socket of said hub, and aclutch-releasing device located within said tap and projecting beyondthe end thereof,snbstantiall y as and for the purpose set forth.

2. The tap-head herein described, consisting of a hub having means forsecuring the end of a tap therein and having connected therewith afriction clutch, and sliding wedgeshapcd blocks connected together by atoggle-joint for locking and releasing the two members of said clutch,in combination with a spindle having projecting lugs for engaging lugsupon one of the members of said clutch, and a tap having centrallydisposed therein a rod or similar device for operating said toggle jointto release said clutch, substantially as ing of spindle A, having acentral bore and projecting lugs, as shown, hub B, having stem 0,adapted to fit loosely in the bore of said spindle, and having at itsopposite end a socket to receive the tap, said socket terminating in thechamber If, blocks b located in a transverse opening in said hub andconnected by links If'with plug b", located in said chamber 0 ring D,secured to said hub and having its inner surface beveled, as shown, ringE, located within said ring D, said ring E having its outer surfacebeveled, as shown, and having projecting lugs 6, spring b located inchamber b above said plug 1) and tap G, having red 0 extendinglongitudinally therethrouglneombined and operating substantially as setforth.

4. In a tap head, the combination, with spindle A, having a central boreterminating in chamber a and having lug a projecting upwardly withinsaid chamber, and orifice a, leading into said chamber, of hub B,provided with the tap receiving socket, friction-clutch, andclutch-releasing devices, substantially as described, said hub havingstem 1), adapted to be inserted within the bore of spindle A and toproject within said chamber a said stem being provided at its upper endwith an orifice extending transversely therethrough, and pin I), adaptedto be inserted through orifice a" of said spindle and seated within theorifice in said stem 1), substantially as and for the purpose described.

5. In a taphead, the combination,with hub B, having a tap-receivingsocket in its lower end, of gib L, located within a recess in the wallof said socket, screw If, secured at its inner end to said gib andhaving its head located within a countersunk depression in said hub, aspring located between the head of said screw and the bottom of saiddepression, and adj usting-screw b", bearing at its inner end againstsaid gib, substantially as and for the purpose described.

6. In a tap head, the combination, with spindle A, having lugs a, of hubB, having flange b, beveled shoulder b and transverse opening 0', wedgeshaped blocks b sliding within grooves in said flange and shoulder, saidblocks being connected together by a toggle'joint, ring E, having itsouter and lower surfaces beveled, as shown, and having lugs e projectingfrom its upper surface, and ring I), having its inner surface beveled tocorrespond with the bevel of the outer surface of said ring E,substantially as and for the purpose described.

SANFORD D. LELAND.

\Vitnesses:

W. H. CHAPMAN, T. M. BROWN,

IIO

